Breaking the Fourth Wall
The Fourth Wall is a literary term that comes from the theater. A stage is usually rectangular, i.e. there are three walls, one at the back and two at the sides. The "fourth wall" is the edge of the stage that faces the audience. Obviously there was no real wall there. The term "fourth wall" refers to the barrier between the audience of a work of fiction and the fictional universe itself. In most fictional works, the fourth wall is intact, i.e. the characters do not acknowledge that there is an audience or that they themselves are part of a fictional work. In some fictions, however, the literary technique of breaking the fourth wall is used. This involves talking to the audience, affecting the "real world", rewriting speech bubbles, acknowledging that they are part of a fictional world, and even leaving the fictional work itself and entering the "real world" (which is, of course, represented by a fictionalized version of the real world).